AVK valves protect drinking water sources from saltwater intrusion

Every year, thousands of tourists gather by the river of Qiantang River in Hangzhou City, China, to experience the phenomenon of the Qiantang Tide. This may look like a tsunami, but actually it is a tidal bore; a wave that flows upstream as high tide approaches. More than 80 rivers around the world have tidal bores. However, the one of the Qiantang River is the world's largest with waves up to 10 m, 3 km wide and a racing speed of 24km/h. Its rumble can be heard more than an hour away before it arrives.

Fascinating, but complicated

More than 80% of the water supplied to the Hangzhou urban area comes from the Qiantang River, and for people living in Hangzhou, this phenomenon is more than just an exciting event. During the tidal flood season, the upward salt tide from the river is threatening drinking water sources for the millions of people living in Hangzhou.

So, in order to coordinate the development of water sources and urban construction, and to reduce the threat of saltwater intrusion, Hangzhou has established a water intake upward movement project to optimise the layout of water intake.

The water intake in Hangzhou was moved to the Shimen Shajiang section of the Fuchun River, and water intake pump stations were built at the Jiuxi water plant. A pipeline project was initiated at the Shansha reservoir, and the existing facilities of the water plant and the reservoir were renovated.

The initial intake pump station was constructed to handle 1.7 million tons/day. However, in the new project the construction of the water intake head, pump station and water pipelines are designed and constructed on the basis of the prospective scale of 3 million tons/day to accommodate for an increasing water need.